Opponents view derailing the bill as a defeat for Gov. Rick Perry, who had declared it an "emergency" legislative issue.

The measure would prevent local government entities from adopting policies to keep law officers from enforcing immigration laws. It passed the House this month amid a heated and emotional debate, with the majority of House Democrats arguing that the measure would lead to racial profiling and ruin the relationship between the state's Hispanics and law enforcement.

The bill was up before the Senate Transportation and Homeland Security Committee on Wednesday afternoon, and supporters hoped it would be cleared for a vote on the Senate floor. Instead, the committee voted 8-0 to replace the entire bill with another one, Senate Bill 9, which addresses a wide range of homeland security issues and has passed the Senate but appears immobilized in the House.

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State Sen. Juan "Chuy" Hinojosa, D-McAllen, proposed the change. Sen. Tommy Williams, R-The Woodlands, the author of SB9 and the committee's chairman, approved of the change and assured wary Democrats on the committee that he wasn't orchestrating a trick designed to sneak a sanctuary city ban onto the Senate floor.

SB9's provisions include requiring law enforcement to check the immigration status of people in custody, which supporters say is more sensible than the broader mandate imposed on law enforcement in the proposed sanctuary cities ban.